Seven years ago, the United States had too much housing stock. Now the country faces the opposite problem: We’ve already worked our way through the overhang of extra homes from the bubble years and are now underbuilding — especially when you consider population growth and the share of young people doubled up with their parents and eager to move out. Homeownership remains a central part of the American dream, and most people, including young renters, still aspire to own their own homes.

In other words, there’s a lot of pent-up demand for housing. Yet home-buying and homebuilding remain curiously anemic by almost any metric, despite low mortgage rates. Residential investment activity as a share of the economy, for example, is lower today than it was at any time in the 60 years leading up to the housing bust.

No one expects or wants things to go back to the crazy building, buying and flipping frenzy we saw during the bubble era. But something is off. What?

Plenty of commentators have blamed a lackluster job market, slow wage growth and the large number of homeowners who remain underwater, which I agree probably are the biggest culprits. But lawmakers are probably playing a role, too, by indefinitely delaying — as they did again last week — the complex, highly technical and special-interest-fraught task of overhauling the housing finance system.

Five years after Fannie Mae and Freddie Mac went into conservatorship, they’re still there. The whole system remains a big, complicated mess, and it probably will remain so for years. At this point, many economists and political analysts with whom I’ve spoken don’t believe anything will change until at least 2017, after the next presidential election.

Look, I’m usually skeptical of the “regulatory uncertainty” explanation for economic mediocrity. But when it comes to the housing finance system, there's good reason to believe that suspended animation is indeed discouraging both mortgage lending and homebuilding and thereby dragging on the entire economy.

“With each passing year that Congress leaves things as they are,” said Mark Zandi, chief economist at Moody’s Analytics, Fannie and Freddie “get more ossified and less willing to innovate.” And if you’re a business that issues mortgages, it’s hard to do any long-term planning around institutions and policies that may or may not exist in a few years.

That uncertainty about the shape of the secondary market for mortgages trickles down to would-be homebuyers in the form of tighter credit. Newly originated mortgages are at their lowest level in more than a decade. Not coincidentally, the share of homes being purchased with cash has been rising — to 42 percent in the last quarter, according to RealtyTrac — even though foreclosures are down and institutional investors (the buyers most likely to be able to afford all-cash transactions) seem to be losing interest.

Of course, cash is king not only because credit is tight but also because there are so few homes for sale: In many markets buyers basically have to offer cash upfront if they’re going to make a successful bid on a sought-after house. But the shortage of homes on the market probably is also related to uncertainty about the future of the housing finance system.

Homebuilders are reluctant to ramp up construction partly because they’re worried about how hardy the overall job market is — but also because they don’t have a great sense of what the credit environment will look like by the time they buy a plot of land, get a building permit, complete construction and put a new house up for sale.

“As these guys start to plan for the next development, they need to know there’s a consistent market out there, and that there will be funds available to American consumers who need to borrow,” Gerald M. Howard, the chief executive officer of the National Association of Home Builders, told me. “That affects how much they build, where they build, and when they build.”

Howard’s organzation had thrown its weight behind the Senate legislation that got effectively tabled last week, so of course he’s disappointed that this particular bill is looking pretty dead. But just as important as getting the rules precisely to builders’ liking, he said, is getting any rules in place at all.

“Builders are entrepreneurs,” he said. “If they know what the rules of the game are, they can find a way to be successful. Not knowing is what’s really, really problematic.” And at least for the time being, lawmakers don’t seem terribly motivated to provide clarity.